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Remittances,financial development and economic growth in sub-Saharan African countries:evidence from a PMG-ARdL approach

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Financial Innovation 2019年第1期5卷 142-166页

作者： d.O.Olayungbo Ahmod Quadri department of Economics Obafemi Awolowo UniversityIle-IfeNigeria

The study investigated the relationship among remittances,financial development and economic growth in a panel of 20 sub-Saharan African countries over the period of 2000 and *** study used both Pooled Mean Group and Mean Group/ARdL estimations with panel unit root and cointegration *** establishing cointegration,remittances and financial development were found to have positive effects on economic growth both in the short and the long *** interactive term showed that financial development acted as a substitute in the remittances-growth ***,unidirectional causal relationships were found to exist from GdP to remittances and from financial development to ***,no causality existed between remittances and financial development in the SSA countries.

关键词： Remittances Financial development Growth PMG/MG-ARdL Granger causality test African countries

Effect of friction coefficients on the dynamic response of gear systems

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Frontiers of Mechanical Engineering 2017年第3期12卷 397-405页

作者： Lingli JIANG Zhenyong dENG Fengshou GU Andrew d. BALL Xuejun LI Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment Hunan University of Science and Technology Xiangtan 411201 China Centre for Efficiency and Performance Engineering University of Huddersfield Huddersfield HD1 3DH UK

The inevitable deterioration of the lubrication conditions in a gearbox in service can change the tribological properties of the meshing teeth. In turn, such changes can significantly affect the dynamic responses and running status of gear systems. This paper investigates such an effect by utilizing virtual prototype technology to model and simulate the dynamics of a wind turbine gearbox system. The change in the lubrication conditions is modeled by the changes in the friction coefficients, thereby indicating that poor lubrication causes not only increased frictional losses but also significant changes in the dynamic responses. These results are further demon-strated by the mean and.root mean square values calculated by the simulated responses under different friction coefficients. In addition, the spectrum exhibits significant changes in the first, second, and third harmonics of the meshing components. The findings and simulation method of this study provide theoretical bases for the development of accurate diagnostic techniques.

关键词： dynamic response friction coefficient wind loads wind turbine gearbox

Energy expenditure and muscular activation patterns through active sitting on compliant surfaces

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Journal of Sport and Health Science 2017年第2期6卷 207-212页

作者： d.Clark dickin Rachel K.Surowiec Henry Wang Biomechanics Laboratory Ball State UniversityMuncieIN 47306USA

Purpose: To test the effectiveness of sitting surfaces with varied amounts of stability on muscle activity and energy ***: Using a within-participants repeated measures design, 11 healthy young-adult females(age = 20.0 ± 1.8 years) were measured using indirect calorimetry to assess energy expenditure, and electromyography to assess muscular activation in trunk and leg musculature under 3different sitting surfaces: flat-firm surface, air-filled cushion, and a stability ball. data were analyzed using repeated measures analysis of variance with follow-up pairwise contrasts used to determine the specific effects of sitting surface on muscle activation and energy ***: Significantly greater energy expenditure was recorded for the stability ball(p = 0.01) and the cushion(p = 0.03) over the flat surface(10.4% and 9.6% greater, respectively), with no differences between the ball and the cushion. Both the ball and the cushion produced higher tibialis anterior activation over the flat surface(1.09 and 0.63 root-mean-square millivolts(RMSmv), respectively), while the stability ball produced higher soleus activity over both cushion and flat surfaces(3.97 and 4.24 RMSmv, respectively). Additionally, the cushion elicited higher adductor longus activity over the ball and flat surfaces(1.76 and 1.81 RMSmv, respectively), but no trunk musculature differences were ***: Compliant surfaces resulted in higher levels of muscular activation in the lower extremities facilitating increased caloric *** the increasing trends in sedentary careers and the increases in obesity, this is an important finding to validate the merits of active sitting facilitating increased caloric expenditure and muscle activation.

关键词： Energy metabolism Electromyography Female Posture Sedentary lifestyle Workplace

Adjustment of Forest Ecosystem root Respiration as Temperature Warms

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Journal of Integrative Plant Biology 2008年第11期50卷 1467-1483页

作者： Andrew J.Burton Jerry M.Melillo Serita d.Frey Ecosystem Science Center Michigan Technological University School of Forest Resources and Environmental Science Michigan Technological University The Ecosystems Center Marine Biological Laboratory department of Natural Resources University of New Hampshire

Adjustment of ecosystem root respiration to warmer climatic conditions can alter the autotrophic portion of soil respiration and influence the amount of carbon available for biomass production. We examined 44 published values of annual forest root respiration and found an increase in ecosystem root respiration with increasing mean annual temperature （MAT）, but the rate of this cross-ecosystem increase （Q10 = 1.6） is less than published values for short-term responses of root respiration to temperature within ecosystems （Q10 = 2-3）. When specific root respiration rates and.root biomass values were examined, there was a clear trend for decreasing root metabolic capacity （respiration rate at a standard temperature） with increasing MAT. There also were tradeoffs between root metabolic capacity and.root system biomass, such that there were no instances of high growing season respiration rates and high root biomass occurring together. We also examined specific root respiration rates at three soil warming experiments at Harvard Forest, USA, and found decreases in metabolic capacity for roots from the heated plots. This decline could be due to either physiological acclimation or to the effects of co-occurring drier soils on the measurement date. Regardless of the cause, these findings clearly suggest that modeling efforts that allow root respiration to increase exponentially with temperature, with Q10 values of 2 or more, may over-predict root contributions to ecosystem CO2 efflux for future climates and underestimate the amount of C available for other uses, including net primary productivity.

关键词： acclimation climatic warming root biomass root respiration soil warming.

Ectomycorrhizal and Saprotrophic Fungal Communities Vary Across mm-Scale Soil Microsites differing in Phosphatase Activity

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Pedosphere 2019年第3期29卷 344-359页

作者： Aaron GOdIN denise BROOKS Sue J. GRAYSTON Melanie d. JONES Biology department University of British Columbia Okanagan campus Kelowna V1V 1V7 (Canada) department of Forest & Conservation Sciences Faculty of Forestry University of British Columbia Vancouver V6T 1Z4 (Canada)

To understand nutrient cycling in soils, soil processes and microorganisms need be better characterized. To determine whether specific trophic groups of fungi are associated with soil enzyme activity, we used soil imprinting to guide mm-scale sampling from microsites with high and low phosphatase activities in birch/douglas-fir stands. Study 1 involved sampling one root window per site at 12 sites of different ages(stands);study 2 was conducted at one of the stem-exclusion stands, at which 5 root windows had been installed. Total fungal and ectomycorrhizal(EM) fungal terminal-restriction fragment length polymorphism(TRFLP)fingerprints differed between high-and low-phosphatase activity microsites at 8 of 12 root windows across 12 sites. Where differences were detected, fewer EM fungi were detected in high-than low-phosphatase activity microsites. Using 5 root windows at one site,next-generation sequencing detected similar fungal communities across microsites, but the ratio of saprotrophic to EM fungal reads was higher in high-phosphatase activity microsites in the two windows that had low EM fungal richness. In windows with differences in fungal communities, both studies indicated that EM fungi were less successful than saprotrophic fungi in colonizing fine-scale,organic matter-rich microsites. Fine-scale sampling linked with in situ detection of enzyme activity revealed relationships between soil fungal communities and phosphatase activity that could not be observed at the scales employed by conventional approaches, thereby contributing to the understanding of fine-scale phosphorus cycling in forest soils.

关键词： ectomycorrhizae fine scale fungal communities phosphatase root windows saprotrophic fungi soil imprinting

Geographical location affects size and materials used in the construction of European Pied Flycatcher(Ficedula hypoleuca) nests

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Avian Research 2019年第2期10卷 111-125页

作者： Kevin B.Briggs Lucia E.Biddle d.Charles deeming Joseph Banks Laboratories School of Life SciencesUniversity of Lincoln

Background: Nest construction is a key element of avian reproductive behaviour and the result is often a complex structure that is used for incubation of eggs, which represents an extended phenotype. It is known that nest construction is a plastic behaviour but the extent to which plasticity is observed in a single species with a wide geographical distribution is largely unknown. This study sought to better understand variation in nest size and composition across a very wide geographical area. The hypothesis suggested that location would affect size but not composition of nests of the European Pied Flycatcher (Ficedula hypoleuca). Methods: Nests and reproductive data were collected from seventeen study sites, spread over 6° of latitude and 3.3° of longitude on the island of Great Britain. dimensions of nests were measured before they were deconstructed to determine the masses and types materials used in the outer nest and the cup lining. Results: Geographical variation was observed in base thickness of nests but not many other dimensions. Nests varied in composition but were mainly made of leaf, moss, bark, grass, root and fern. Moss was used more to the north and east of the study area compared with more leaf mass towards the south and west. The species of leaf and bark used in the nests varied between geographical locations. Additionally, the use of leaves or bark from a particular tree species did not reflect the incidence of the tree species in the immediate territory. Conclusions: This study showed that nest composition was affected by geographical location over a wide area. Variation between nests at each location was high and so it was concluded that differences in nest composition reflect individual selection of materials but evidence is such that it remains unclear whether this is deliberate to fulfil a specific role in the nest, or simply opportunistic with birds simply picking up materials with the appropriate characteristics as they find them outside the

关键词： Breeding success Ficedula hypoleuca Latitude Longitude Nest composition Nest size Nest structure

Seedling survival after simulating grazing and drought for two species from the Pamirs,northwestern China

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Plant diversity 2022年第6期44卷 607-616页

作者： Fiona R.Worthy Stefanie d.Goldberg Sailesh Ranjitkar Jian-Chu Xu CAS Key Laboratory for Plant diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201YunnanChina CIFOR-ICRAF China Program World Agroforestry(ICRAF)Kunming 650201YunnanChina Honghe Center for Mountain Futures(CMF) Kunming Institute of BotanyChinese Academy of SciencesHonghe County 654400YunnanChina Faculty of Agroforestry Lumbini Buddhist UniversityLumbiniNepal

For plant populations to persist,seedling recruitment is essential,requiring seed germination,seedling survival and *** and grazing potentially reduce seedling recruitment via increased mortality and reduced *** studied these seederelated processes for two species indigenous to the Pamir Mountains of Xinjiang in northwestern China:Saussurea glacialis and Plantago *** collected from Taxkorgan,Xinjiang,had a viability rate of 15.8%for *** but 100%for *** the viable seeds,the highest germination rates were 62.9%for *** and 45.6%for *** a greenhouse experiment,we imposed a series of stressful conditions,involving a combination of simulated grazing and drought *** had the most severe impact on younger *** showed that 89%of *** mortality was due to early simulated grazing,whereas 80%of *** mortality was due to early simulated *** differences could contribute to their differing *** may rely on water storage in leaves to survive drought events,but showed no shifts in biomass allocation that would improve grazing *** appears more reliant on its root system to survive grazing,but the root reserves of younger plants could be insufficient to grow deeper in response to *** applying all mortality factors,17.7 seedlings/parent of *** survived,while onlydlings/parent of *** survived,raising concerns for its capacity to persist in the *** genetic differences may underlie the two species’contrasting grazing and drought ***,differing conservation strategies are required for their utilization and protection.

关键词： Medicinal plant Pastoralist Plantago lessingii Saussurea glacialis Soil moisture Water deficit

K＋ Transporter AtCHX17 with Its Hydrophilic C Tail Localizes to Membranes of the Secretory/Endocytic System： Role in Reproduction and Seed Set

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Molecular Plant 2013年第4期6卷 1226-1246页

作者： Salil Chanroj Senthilkumar Padmanaban daniel d. Czerny Guang-Yuh Jauh Heven Sze department of Cell Biology and Molecular Genetics and Maryland Agricultural Experiment Station University of Maryland College Park MD USA department of Plant Science and Landscape Architecture University of Maryland College Park MD USA Present address: department of Biotechnology Faculty of Science Burapha University Chon-Buri 20131 Thailand Institute of Plant and Microbial Biology Academia Sinica 128 Academia Road Section 2 Nankang Taipei

The importance of sorting proteins and wall materials to their destination is critical for plant growth and development, though the machinery orchestrating membrane trafficking is poorly understood. Transporters that alter the environment across endomembrane compartments are thought to be important players. Using Escherichia coli and yeast, we previously showed that several Arabidopsis Cation/H＋ eXchanger （AtCHX） members were K＋ transporters with a role in pH homeostasis, though their subcellular location and biological roles in plants are unclear. Co-expression of markers with CHX16, CHX17, CHX18, or CHX19 tagged with a fluorescent protein indicated these transporters associated with plasma membrane （PM） and post-Golgi compartments. Under its native promoter, AtCHX17（l_820）-GFP localized to prevacuolar compartment （PVC） and to PM in roots. Brefeldin A diminished AtCHX17- GFP fluorescence at PM, whereas wortmannin caused formation of GFP-labeled ring-like structures, suggesting AtCHX17 trafficked among PVC, vacuole and PM. AtCHX17（1-472） lacking its carboxylic tail did not associate with PVC or PM in plant cells. Single chx17 mutant or higher-order mutants showed normal root growth and vegetative devel- opment. However, quadruple （chx16chx17chxlSchx19） mutants were reduced in frequency and produced 50%-70% fewer seeds, indicating overlapping roles of several AtCHX17-related transporters in reproduction and/or seed devel- opment. Together, our results suggest that successful reproduction and seed development depend on the ability to regulate cation and pH homeostasis by AtCHX17-1ike transporters on membranes that traffic in the endocytic and/or secretory pathways.

关键词： membrane trafficking pH homeostasis cation/proton antiporter prevacuolar compartment.

Iron- and Ferritin-dependent Reactive Oxygen Species distribution： Impact on Arabidopsis root System Architecture

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Molecular Plant 2015年第3期8卷 439-453页

作者： Guilhem Reyt Soukaina Boudouf Jossia Boucherez Frédéric Gaymard Jean-Francois Briat Biochimie et Physiologie Moléculaire des Plantes Centre National de la Recherche Scientifique Institut National de la Recherche Agronomique Université Montpellier 2 SupAgro. Bat 7 2 place Viala 34060 Montpellier Cedex 1 France present address: Institute of Biological and Environmental Sciences University of Aberdeen Cruickshank Building St Machar Drive Aberdeen Scotland AB243UU UK

Iron （Fe） homeostasis is integrated with the production of reactive oxygen species （ROS）, and distribution at the root tip participates in the control of root growth. Excess Fe increases ferritin abundance, enabling the storage of Fe, which contributes to protection of plants against Fe-induced oxidative stress. AtFerl and AtFer3 are the two ferritin genes expressed in the meristematic zone, pericycle and endodermis of theAra- bidopsis thaliana root, and it is in these regions that we observe Fe stained dots. This staining disappears in the triple ferl-3-4 ferritin mutant. Fe excess decreases primary root length in the same way in wild-type and in ferl-3-4 mutant. In contrast, the Fe-mediated decrease of lateral root （LR） length and density is enhanced in ferl-3-4 plants due to a defect in LR emergence. We observe that this interaction between excess Fe, ferritin, and.root system architecture （RSA） is in part mediated by the H_2O_2/O2·^- balance between the root cell proliferation and differentiation zones regulated by the UPB1 transcription factor. Meristem size is also decreased in response to Fe excess in ferritin mutant plants, implicating cell cycle arrest mediated by the ROS-activated SMR5/SMR7 cyclin-dependent kinase inhibitors pathway in the interaction between Fe and RSA.

关键词： roots development oxidative stress reactive oxygen species balance iron ferritins